The present invention relates to the field of electric road vehicles in general, and more particularly to improvements in apparatus at battery replacement or relay stations where spent energy sources (hereinafter called batteries or motive-power batteries) of such vehicles are replaced with fresh (recharged) batteries.
It is already known to utilize a trolley, dolly or another suitable conveyance for transport of spent and fresh batteries at relay stations where spent motive-power batteries are removed from and fresh batteries are inserted into or otherwise secured to road vehicles. Reference may be had to German Offenlegungsschrift No. 2,214,647. Motive-power batteries are often rather heavy and bulky so that the use of a conveyance contributes significantly to convenience of replacement of spent batteries as well as to a reduction of the interval of halt of battery-operated road vehicles at relay stations. The aforementioned German publication discloses a conveyance which can receive a spent battery and facilitates the transfer of a fresh battery into or onto the road vehicle provided that the vehicle is moved to a predetermined position with respect to the conveyance. As a rule, the positioning means for vehicles includes a recess or socket in the floor or ground at the relay station, and the driver of the vehicle must manipulate the vehicle with great care in order to insure that a wheel will actually enter the socket, i.e., that the spent battery will be readily accessible for transfer onto the conveyance. Proper positioning involves placing a side of the vehicle into accurate register with the conveyance (or with the path for the conveyance) as well as accurate orientation of the vehicle with respect to a vertical axis. Such orientation can present serious problems, especially if the driver is inexperienced. In fact, even a highly skilled operator is likely to spend a relatively long period of time in order to properly orient the vehicle with respect to the conveyance. As a rule, proper orientation involves moving the vehicle to a position which deviates only negligibly from an optimum position; in most instances, the deviation cannot exceed one or more centimeters, not only as considered in the longitudinal direction of the vehicle but also as regards its orientation with respect to a vertical axis.
The provision of a socket in the floor or ground at the relay station for battery-operated road vehicles is satisfactory only when the position of the battery with respect to the wheel which enters the depression is identical for each battery-operated vehicle. However, such socket will not insure satisfactory positioning of different types of vehicles wherein the batteries are located at different distances from the front and/or rear wheels and/or at different levels. For example, certain battery-operated vehicles have battery compartments which can be reached from below (i.e., at the underside of the chassis), and certain other types of vehicles have battery compartments which are accessible at the one or the other side of the chassis. Moreover, the provision of a single socket does not insure that the inclination of the chassis (i.e., of the battery compartment which is normally provided in the chassis) will correspond to an optimum inclination, especially if the removal of spent batteries and the insertion of fresh batteries is to be carried out semiautomatically or in a fully automatic way.